Don't rely on include_path to include files.

Always use dirname() or, once available, ABSPATH.

props ketwaroo, hakre.
fixes #17092.

Built from https://develop.svn.wordpress.org/trunk@25616


git-svn-id: http://core.svn.wordpress.org/trunk@25533 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/options-discussion.php

@@ -7,7 +7,7 @@
  */
 
 /** WordPress Administration Bootstrap */
-require_once('./admin.php');
+require_once( dirname( __FILE__ ) . '/admin.php' );
 
 if ( ! current_user_can( 'manage_options' ) )
 	wp_die( __( 'You do not have sufficient permissions to manage options for this site.' ) );
@@ -28,7 +28,7 @@ get_current_screen()->set_help_sidebar(
 	'<p>' . __('<a href="http://wordpress.org/support/" target="_blank">Support Forums</a>') . '</p>'
 );
 
-include('./admin-header.php');
+include( ABSPATH . 'wp-admin/admin-header.php' );
 ?>
 
 <div class="wrap">
@@ -249,4 +249,4 @@ echo apply_filters('default_avatar_select', $avatar_list);
 </form>
 </div>
 
-<?php include('./admin-footer.php'); ?>
+<?php include( ABSPATH . 'wp-admin/admin-footer.php' ); ?>